Your TPU 3D Printing Questions Answered

Industrial manufacturers 3D print with TPU to produce durable parts with rubber-like properties, without the need for casts or molds. It can stretch more than 5x its original shape before failing.

Parts printed in TPU have the rubber-like material’s elasticity, shock absorption, impact resistance, vibration dampening, and potential for elongation. TPU is also a very durable material, with high resistance to abrasions, chemicals, oil, and low temperatures, as well as a moderate resistance to water.

TPU filament is available in varying levels of hardness. Varying levels of flexibility can also be achieved through alternating the level of infill. A lower infill density will yield a more flexible part, whereas a higher infill can make the part more rigid. Furthermore, TPU filament is available in many different colors.

Manufacturers often 3D print TPU for industrial and consumer parts that require a combination of durability and its rubber-like properties described above. These parts include:

• Gaskets

• Seals

• Shock absorbers/vibration dampening components

• Non-marring workholding

• Flexible valves

• Friction pads

• Hoses

• Drive belts

• Straps

• Bands

• Protective coverings

• Sporting equipment

• Prosthetics

• Industrial applications that demand flexibility, elasticity, and/or durability.

TPU 3D printing provides the ability to quickly and efficiently make industrial-grade rubber-like parts in low volumes. This unlocks use as an ideal production means for customized, one-off uses — such as custom insoles, watch bands, prosthetic equipment, and more.

Manufacturing the same custom-shaped flexible parts through conventional methods is highly inefficient — it demands production of one-off tooling first, which significantly increases total costs and lead times, and makes low-volume unit economics unfavorable.

Other types of flexible 3D printer filaments in the same TPE family (Thermoplastic Elastomer), are available. However, other TPE filaments are not as useful for industrial applications: they aren’t as strong and durable, and are more difficult to print.

Example: The Central Virginia VA Health Care System uses TPU 3D printing for production of customized assistive prosthetics. Flexible, custom stylus holder splints allow disabled veterans with compromised grip strength, motor skills, or hand dexterity to use pens and other writing utensils.

Here, 3D printing TPU with Markforged allows the VA to design and produce effective customized prosthetics quickly without one-off casting.

TPU can be a tricky material to 3D print. Compared to stiffer materials, soft and bendable filaments are generally more difficult to print.

While TPU can be more challenging to print than plastics, following this set of recommendations can improve the probability of a successful print for most TPU 3D printers:

• Avoid printing too quickly or with incorrect nozzle

• temperatures or retract settings

• A print speed of 5-30 mm/s is often recommended for TPU

• Use a slow, consistent feed rate

• Use a negative tolerance between the parts

• Avoid using rafts

To address the historical challenge of 3D printing TPU, Smooth TPU-95A on the Digital Forge offers a more reliable, simple way to 3D print this material with consistent results. Users can simply hit ‘print’ without needing an engineer to configure print speeds, nozzle temperatures, and retract settings.

TPU vs. PLA: Similar to TPU, PLA (polylactic acid) is another widely used 3D printing filament. While both are popular 3D printing materials, manufacturers use them for different applications. PLA is much stiffer and less flexible than TPU. In the industrial manufacturing space, PLA is usually reserved for prototypes, while 3D printed TPU parts are found in many customizable end-uses that demand flexibility and strength.

Generally speaking, TPU is more challenging to 3D print than PLA, which does not frequently cause jamming, stringing, or clogging.

Is TPU better than other TPEs? While other TPE filaments are available to 3D print flexible parts, they are less strong, less durable, and are more challenging to successfully print. As a result, TPU is the most popular material for printing flexible parts on demand.

TPU vs. Onyx: Harder, stiffer production materials such as Onyx—micro carbon fiber-filled Nylon—should be used for parts with moderate to significant heat and functional loads. Printing Onyx will also yield a better surface finish, and the parts can be reinforced with continuous fibers for additional strength and material properties.

While there are a number of available 3D printers that are capable of printing this material, not printers compatible with TPU are equal. When working with a notoriously finicky material to print, using a high-quality, industrial-grade printer can improve the rate of successful prints while simplifying the process.

Markforged Smooth TPU 95A is compatible with the Onyx Pro (Gen 2), Mark Two (Gen 2), X3 (Gen 2), X5 (Gen 2), and X7 (Gen 2), and Industrial Gen 1 printers with the A3648 extruder installed. With Markforged Smooth TPU 95A, users can simply hit ‘print’ for flexible TPU parts on demand — no need for an engineer to tweak print speeds, nozzle temps, or retract settings.